Safety cover for machinery



y 1950 I H. F. LATHAM 2,508,460

SAFETY COVER FOR MACHINERY Original Filed Jan. 18, 1946 4 Sheets-Sheet 1 HFIRRY FREbEmg K LHTHHM Attorney 3 May 23, 1950 H. F. LATHAM 2,508,460

SAFETY COVER FOR MACHINERY I Original Filed Jan. 18, 1946 4 Sheets-Sheet 2 7/71/9/71'0 HARRY FREDERICK LHTHHM Attorneys May 23, 1950 H. F. LATHAM SAFETY COVER FOR MACHINERY 4 Sheets-Sheet 3 Original Filed Jan. 18, 1946 FIG. 3,

- Inventor HHRRY FREDERICK LQTHHM After/78118 y 1950 H. F. LATHAM 2,508,460

SAFETY COVER FOR MACHINERY Original Filed Jan. 18, 1946 4 Sheets-Sheet 4 FIG. 4.

f 1 I g 56 i 54 I l 5v k I m 4 63 1 47% 46 49 4;; iii i 33/ 55 34 v I f f #1/ lllllll H R BY "W ATTORNEYS Patented May 23, 1950 SAFETY COVER FOR MACHINERY Harry Frederick Latham,

Walton-on-Thames,

England, assignor to Elliott Brothers (London) Limited, London, England, a company of Great Britain and Northern Ireland Original application January 18, 1946, Serial No. 642,025. Divided and this application July 17,

1947, Serial No. 761,683.

February 5, 1945 2 Claims.

This invention relates to safety covers for machinery, and more particularly for power driven apparatus for the mechanical treatment of food, and is applicable with advantage to so-called bowl cutting machines. In a preferred form of the invention, this machine and a mincer are arranged in a common frame. The invention has for its object to provid improved safety covers which while giving a large amount of safety, can be readily removed under safe conditions. Another object is to provide an improved safety icover which is relatively inexpensive to manufacure.

Other objects and features of the invention will be ascertained from the following description, by way of example, of a food-preparing machine incorporating the present invention. In the drawings Fig. 1 is a plan View of a combined bowl cutting machine and mincer, while Figs. 2 and 3 are sectional elevations on lines 2X2X, and 3X-3X respectively, and Fig. 4 shows part of Fig. 3 at a larger scale.

Referring now to the drawings l is the common frame of the combined bowl cutting machine and mincer, and 2 is a bowl for the bowl cutting machine, which is supported by a ball bearing 3 for rotation about a vertical axis. 5 is the knife head which carries three knives 54, 55 and 5B of the bowl cutting machine and is adapted to rotate about a horizontal axis. Accidental access to the knife head 5 during the operation of the machine is prevented by a protective hood or safety cover 6. Under this safety cover 5, a, comb 49 cooperates with the knives 54, 55 and 56 which pass through its slots. An electric motor (not shown) is provided to drive a main shaft l2 in the frame I of the machine, which serves to drive the knife spindle 5| through a belt drive l3 and also serves to rotate the bowl 2. A worm shaft I5 is driven by shaft l2 through belt drive I4 and carries a Worm lll'meshing with a worm wheel II, .which, through a free-wheel device 35, drives the vertical shaft I 8 which is mounted in a ball bearing 3, and which carries bowl 2. The cover 6 is pivoted about a hinge pin 3| which, according to the present invention, is permanently mounted in the cover '6. The stationary part of the hinge consists of a bracket 6| which is secured to the frame I of the machine. Slots 4'! are provided in the bracket 6| to receive the hinge pin 3|, and the comb 49 of the machine is provided with one or more extensions 63 which, when the comb is secured in its operative position, extend across the slot 41 and close it on top of the hinge pin 3| so as to prevent the hinge pin 3| from being In Great Britain lifted out of the slot 47. The comb 49 with its extension 63 is held in position by a bolt 44 which passes through the comb 49 and has on its outer end a knob 45 suitably shaped for hand operation, while a screw-threaded end 46 at its other end engages into a tapped hole provided in the bracket 6|. Alternatively, the bolt 44 may be permanently screwed into the tapped hole in bracket 6|, the knob 45 being in this case made as a nut adapted to be screwed into the free end of the bolt 44. In either case it will be seen that when the comb 49 is secured in position by operation of the knob 45, it is impossible to remove the cover 6 from the bowl cutting machine without first opening it by pivotal movement about its 'hinge, since the cover 6 when in its closed position prevents access to the knob 45. Suitable means, for example, such as will be described further on, are also provided to prevent opening of the cover 6 when the machine is in operation, while a short-stroke switch 34, for example a microswitch such as described in the specification of U. S. Patent 1,950,020, is preferably provided to prevent the machine from being put into operation unless the hinge has been properly assembled and secured in position.

In the machine as illustrated, the switch 34 has a plunger 33 which when cover 6 is closed and knob 45 has been screwed down, is pressed back by a projection 32 of the hinge pin 3| to close an electric circuit for the operation of the machine, while when knob 45 is partly or wholly unscrewed, the pressure of a return spring acting on plunger 33 will be sufficient to slightl lift the hinge pin 3| and thus break the circuit for the operation of the machine. The circuit will also be broken if the knob 45 remains in its loading position but cover 6 is opened by a movement about the hinge pin 3| since in this case the projection 32 on the hinge pin 3| will move along the groove indicated at '48 out of the path of the plunger 33, this plunger being thus allowed to moved outwardly, thus again interrupting the electric circuit for the operation of the bowl cutting machine. Disposed laterally of the bowl cutting machine, a feeding tray 1 is mounted on the frame I for a mincer which may be of the type described in the specification of British Letters Patent No. 512,805. It comprises a worm B in a chopper head 9 and is arranged underneath the tray '4, from which the food to be minced is supplied to the mincer through a chute Ill. An electric motor ll drives the mincer through suitable reducing gearing, enclosedin a gear box 51. During operation of the bowl cutting machine, the cover 6 of the machine is held in position by-a hand lever I9 (Fig. 1) which is cover from being opened. When, in order to permit opening of the cover 6, lever I9 is shifted to the position shown in chain-dotted lines, a drum 2| having a cut-off portion at 22 is rotated with the lever. A switch 23, preferably a microswitch as described in the specification of U. S. Patent 1,950,020 or some other short-stroke switch, cooperates with drum 2! in such a manner that when lever I9 is moved out of the locking 120- sition, the recessed portion 22 of the drum 2! allows the plunger 24 of switch 23 to move into the circuit-breaking position of the switch. At the same time a steel band 25 passing over a pulley 26 to a weight 21 on a lever 28 is released by the rotation of drum 2|, so that weight 2? will apply tension to a brake band 29 which acts on a brake drum 30 mounted on shaft l2. It will thus be evident that when lever I9 is moved to permit opening of the cover 6, the electric circuit for the motor driving the bowl cutting machine is interrupted by means of switch 23, while at the same time a brake 21, 28, 29 is applied to th drive of the bowl cutting machine, so as to prevent the knives 54, 55, 56 from being rotated and the bowl 2 from being driven. In view of the above-described arrangement of switch 3 5, it will further be evident that when cover 6 is opened by pivotal movement about the axis of pin 3! so as to permit access to the knives 54, 55, B, projection 32 will move away from the plunger 33 thus allowing switch 34 to break the electric circuit for the motor drive of the knives -54, 55, 5t and bowl 2. The provision of this second circuit breaker in the circuit of the electric motor removes the danger that after opening of the cover 5, the driving motor may be put into operation again by returning handle l9 to the position as shown in full lines in Fig; 1. Onthe other hand, during cleaning of the knives it is desirable to turn handlever 19 to this position so as to release the brake for the drive of the cutting knives and the bowl, thus permitting the knives and bowl to be moved by hand for convenient cleaning thereof. In order to facilitate manual rotation when it is desired to rotate the bowl faster than the rate at which it is mechanically driven, worm wheel I! is rotatably mounted on the driving shaft 18 of the bowl, a free-Wheel mechanism being provided between worm wheel ii and a driving head 35, which latter is secured for common rotation with the shaft P3; The outside of frame l is provided with a sheet-metal or similar covering 38 which prevents accidental access to any part of the drive and injuries that might be caused therebi as well as preventing dust developing inside of the drive from contaminating food in the machin or elsewhere in the room containing it. A hinged table 31 is normally accommodated as shown in a recess provided in the metal covering 36 and can be tilted to the position in which its is shown in chaindotted lines, in which it is adapted to carry a bowl for receiving the food which leaves the mincer 8, 9. Any suitable means may be employed for holding table 31 in its working position when required. The means shown in the drawing, merely by way of example,consist of a spring-biased locking pin 38 adapted to enter into a recess 39 provided in the hinge pin 40 for thetable 31. Frame I rests on feet which are provided with rubber cushioning 41, one of the feet being provided with an adjustment spindle 42. By rotation of this spindle a plate 43 which rests on the rubber cushioning 4| may be raised or lowered, this vertical adjustment serving to ensure a firm stand of the machine irrespective of the condition of the floor. It will be obvious that .the ma'chine as described may be varied in a number of details without departing from the scope of the present invention. This application is a division of patent application Serial No. 642,025, filed January 18, 1946, now abandoned.

I claim:

1. In a food cutting machine [having a hollow container for the food to be treated, a hinged cover for closing the container, a knife located within the container and an electric motor for driving the knife during a food cutting operation, a safety switch assembly'comprising a hinge pin for the cover rigidly fixed therein and having a radial cam projection formed thereon, a halfbearing for the pin located on the machine structure adjacent th edge of the hollow container and provided with a clearance formation to accommodate the cam projection on the pin during rotation thereof, a plunger projecting radially through the half-bearing and biased into engagement at its one end with the 'cam projection to urge the pin off the bearing surface, a switch in the circuit of the electric motor and operatively connected to the plunger so as to be opened when the cover is raised, and a comb detachably secured to the machine structure for co-operating with the knife and having a portion formed to engage the hinge pin and retain it against displacement from the bearing surface of the half-bearing.

2 In a food cutting machine having a hollow container for the food to be treated, a hinged cover for closing the container, a knife locate within the container and an electric motor for driving the knif during a food cutting operation, a safety switch assembly comprising a hinge pin rigidly fixed in the cover and having a cam projection formed radially thereon, a bracket mounted on the machine structure adjacent the rim of the container, an upwardly open halfbearing located on the bracket to receive the hinge pin and having a clearance formation for the cam projection, a plunger projecting radially upwards through the half-bearing, means for biasing the plunger into engagement with the carn'projeetion to'urge the hinge pin off the bearing surface, a switch controlling the motor circuit and secured to the bracket below the half-bearing for operation by the plunger, and a comb detachably se cured to the bracket to co-opera-te with the knife and formed to engage and retain the pin in the half-bearing. V I a a 1 HARRY FREDERICK LATI-IAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITE STATES PA'IENTS 

